In commonly assigned U.S. Pat. Nos. 3,665,924 and 3,740,994, a novel cartridge and instrument for ligating and dividing organic structures by means of surgical staples are disclosed. The present invention relates to a cartridge which, together with an instrument such as disclosed in the commonly assigned patents, is similarly capable of mechanically and repetitiously ligating and dividing organic structures, such as blood vessels and the like.
The cartridge of the present invention is adapted to operate in three stages such as disclosed in the commonly assigned patents. Once the organic structure is inserted within the area of its jaws, the main body and wrap of the cartridge are moved forward toward an anvil member fixed relative to the instrument, thereby enclosing the structure within the jaws of the cartridge. Then a pair of pusher elements is advanced and moves a pair of staples toward the anvil assembly. During the forward portion of the pusher stroke, the respective staples encircle the structure at spaced locations and are crimped about the structure in such a manner that the structure is sealed at two locations. Finally, and with the pushers at the forwardmost portions of their strokes, a knife blade advances and divides the structure intermediate the two staples. The staple closure and crimping sequence is disclosed in commonly assigned U.S. Pat. No. 3,683,927.
The instrument disclosed in the commonly assigned patents is of three stage-design. The forward end of the instrument is provided with three saddles which associate, respectively, with the cartridge wrap, the pushers and the knife of the three-stage cartridge disclosed therein. Three spring elements are housed in the instruments and, in conjunction with a trigger element, operate the cartridge wrap, the pushers and the knife through the three saddle elements. With a cartridge mounted on the instrument, the initial squeezing of the handle moves the cartridge wrap toward the fixed anvil assemblies, and the further squeezing overcomes the force exerted by one of the springs and advances the pushers toward the respective anvils and ultimately, after overcoming the force exerted by another of the springs, urges the knife toward the front of the instrument to effect a severing operation.
In commonly assigned U.S. Pat. No. 3,955,581, a three-stage instrument is also disclosed for operating a cartridge by means of three saddle elements. One of the saddle elements, controlling the pusher, is in direct mechanical association with a trigger operable by the surgeon. One of the remaining saddle elements, controlling the closing of the jaws, is operable in response to the position of the trigger-controlled saddle element through the means of a novel shifter dog arrangement. The third saddle element, controlling the knife of the cartridge, is actuated by a linkage whose operation is controlled directly by the trigger. In this manner, the drawbacks associated with the multiple biasing springs in commonly assigned U.S. Pat. Nos. 3,665,924 and 3,740,994 are avoided.
Although these prior art instruments and cartridge have proved satisfactory in practice, there are certain disadvantages associated with the cartridge. First, because of the cartridge design, the instrument is required to have a three-stage operation. This makes the instrument more complicated to design and engineer and to manufacture. Moreover, the cartridge is designed to advance the staples and transfer them out of the index plane into the plane of the pushers by means of a complex staple feeding arrangement which takes the form of a pair of interacting leaf spring assemblies. This in turn requires close tolerances to be maintained in the manufacture of the cartridge. Also, the cartridge does not have means for locking the cartridge components in position during shipment and prior to mounting the cartridge on the instrument (or means for preventing the inadvertent actuation of the knife after, for example, all of the staples have been expelled from the cartridge) which is as easy to engineer and manufacture as is desired.
Accordingly, it is a broad object of this invention to provide a new cartridge design for ligating and dividing an organic structure.
It is another object of this invention to provide a new cartridge design which will ligate and divide organic structures by means of association with a two-stage instrument.
It is still another object of this invention to provide a new cartridge design in which the associated instrument powers the knife and pushers and the knife is so associated with the main body portions and wraps of the cartridge that the jaws of the cartridge are closed and opened as the knife is moved forward and backward.
It is yet another object of this invention to provide a new cartridge design which has improved means for advancing, forming, and ejecting the staples.
Another object of this invention is to provide a new cartridge design which has improved means for advancing the staples toward the anvil assembly in readiness for ejection.
Still another object of this invention is to provide a new cartridge design which has improved means for locking the cartridge during shipment and preventing the inadvertent severing of organic structures when all of the staples, for example, have been expelled from the cartridge.
These and other objects of the invention, as well as many of the attendant advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the drawings.